Each coloured line here represents the path taken by a different bundle of DNA (known as a chromosome) during meiosis – the unique form of cell division that spawns sperm and egg cells. Each chromosome is dragged like a fish on a line around the inside edge of the cell nucleus by protein motors. On the left is the path taken by DNA in a healthy cell, the right in a cell whose motors have been disabled. During meiosis, chromosomes must match up with their complementary twin, so like singletons at a speed dating session they dart around in a frantic search. Without free movement the chromosomes in the cell on the right never got the chance to encounter their partner. Such mismatching can lead to major developmental problems, so revealing how chromosomes find each other is a high priority for scientists.
Written by Anthony Lewis
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.